A 40-GHz 4-Bit Digitally Controlled VGA with Low Phase Variation Using 65-nm CMOS Process

Jeng Han Tsai, Chia Lung Lin

Research output: Contribution to journalArticle


A 40-GHz variable gain amplifier (VGA) with 4-bit digital gain control and low phase variation is designed and fabricated on the 65-nm CMOS process. The digital gain control mechanism is achieved using the presented digital version current steering topology. The measured gain of the VGA is between 22 and 6 dB at 40 GHz with 16 different linear-in-decibel gain states. Using the proposed two-stage digital version current steering VGA phase compensation technique, the measured phase variation is 3.18° within a 16-dB gain control range (GCR) and the root mean square (rms) phase error is 0.89° at 40 GHz.

Original languageEnglish
Article number8856253
Pages (from-to)729-732
Number of pages4
JournalIEEE Microwave and Wireless Components Letters
Issue number11
Publication statusPublished - 2019 Nov



  • Current steering
  • digital control
  • low phase variation
  • millimeter-wave (MMW)
  • variable gain amplifier (VGA)

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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